1. Field of the Invention
The present invention relates to a member for a ball grid array (hereafter referred to as BGA) semiconductor package and a manufacturing method of a BGA semiconductor package made of such member, and in particular, to a BGA semiconductor package member and a method for manufacturing a BGA semiconductor package using such member by employing a specially designed carrier frame and substrate which drastically improves production, yet requires the use of conventional semiconductor package manufacturing equipment.
2. Description of the Background Art
There have been many efforts to produce highly integrated multi-pin semiconductor packages. For example, a BGA semiconductor package having a plurality of solder balls attached to the substrate to be used as external terminals has been introduced. Because the BGA type package is formed by attaching a plurality of solder balls onto the lower surface of the substrate which are held together by applying heat from a furnace thereto, there are advantages in that the external terminals do not bend easily from external impacts, and that manufacturing characteristics are improved.
The conventional method of manufacturing a typical substrate for a BGA semiconductor package and of a BGA semiconductor package itself is described as follows, with reference to FIGS. 1 through 6.
First, to manufacture a BGA semiconductor package, a substrate for receiving a semiconductor chip is produced. FIGS. 1A through 1F show the conventional substrate during the conventional manufacturing process. As shown in FIG. 1A, both surfaces of a rectangular aluminum panel 1 are anodized. Chrome is sputtered onto the upper surface of the aluminum panel 1 to form a chrome seed layer 2, as shown in FIG. 1B. A photoresist pattern 3 is formed on the chrome seed layer 2 and then, copper 4, nickel 5 and gold 6 are consecutively deposited onto portions of the exposed chrome seed layer 2 which are not covered by the photoresist pattern 3, as depicted in FIG. 1C. Thus, wiring 4A comprising a triple layered configuration of copper 4, nickel 5 and gold 6 is formed.
Afterwards, the photoresist pattern 3 of FIG. 1C is removed by stripping and certain upper surface portions of the aluminum panel 1 are exposed by etching the chrome seed layer 2 using the wiring 4A as a mask. A solder mask 7 is partially applied to the wiring 4A and to the exposed portions of the aluminum panel 1 to form the structure shown in FIG. 1D.
Then, as shown in FIG. 1E, a chip cavity 8 having a certain depth is formed on the upper central portion of the aluminum panel 1. As shown in FIG. 1F, a cutter 9 is used to perform dicing of the aluminum panel 1 by cutting along the dotted lines to thusly produce a substrate 10 to be used for manufacturing a BGA semiconductor package.
FIG. 2 is a flow chart showing the steps of manufacturing a substrate for a conventional BGA package of FIGS. 1A to 1F. A method for manufacturing a BGA package using the substrate 10 made by the above described method is described as follows.
First, a boat 11 used for simultaneously packaging a plurality of chips as shown in FIG. 3 is prepared. The boat 11 has a plurality of chip receiving portions 12a, whereby the edges of the boat allow a chip to be mounted thereon and held in place by clips 11a. On the outer periphery of the boat 11, a plurality of align holes 12 are formed to allow positioning of the manufacturing equipment and the boat 11 during the package manufacturing process.
As shown in FIG. 4A, the substrate 10 of FIG. 1F is placed on the chip receiving portion 12a formed on the boat 11, and is held in place by clips 11a. FIG. 4B is a front view of the boat 11 having a substrate 10 thereon seen from the direction of the arrows.
The processes shown in FIGS. 5A to 5E are then performed. Although these figures only depict the process of packaging a single semiconductor chip on a single substrate, in actuality, a plurality of semiconductor chips are simultaneously packaged on the plurality of substrates of the boat 11. In other words, the boat 11 accommodates a plurality of individual substrates 10 so that a plurality of semiconductor chips are packaged simultaneously to improve production of semiconductor package elements.
The processes shown in FIGS. 5A to 5E are explained in detail as follows.
As shown in FIG. 5A, a die bonding process for fixedly attaching a chip 12 using an adhesive 13 onto the lower surface of a chip cavity 8 formed in the substrate 10 is performed. As shown in FIG. 5B, a wire bonding process is performed, whereby a plurality of chip pads (not shown) formed on the upper surface of the semiconductor chip 12 are connected with wiring 4A formed on the substrate 10 via metal wires 14. Then, as shown in FIG. 5C, a dam forming process is performed, whereby a dam 16 having a predetermined height is formed onto the upper surface of the substrate 10 using a liquid encapsulant of high viscosity which is applied with a dispenser 15 in order to surround the outer periphery of the chip 12.
Afterwards, as shown in FIG. 5D, a potting process is performed, whereby potting is done by using a low viscosity encapsulant using a dispenser 15 at the inner sides of the dam 16 to encapsulate the chip and metal wiring. As shown in FIG. 5E, a solder ball attach process is performed by attaching a plurality of solder balls 18 to achieve electrical connection with the wiring 4A on the upper surface of the substrate 10. Afterwards, the plurality of solder balls are fusingly attached through heat compression using a reflow process, and the residue flux generated during the reflow process is removed by a cleaning process.
After all of the above steps are finished, the BGA semiconductor package is completed by separating each of the substrates 10 from the boat 11. The above conventional BGA semiconductor package manufacturing method flow diagram is shown in FIG. 6. However, the above conventional BGA semiconductor package manufacturing method has many problems.
Firstly, conventional semiconductor package manufacturing equipment which use a lead frame cannot be employed because a specially designed boat and substrate are used to make the above conventional BGA semiconductor package. Thus, the cost of production is high due to the need for equipment to process the specially designed boat and substrate.
Secondly, processing must be carried out by hand in order to attach the substrate 10 onto the upper surface of the boat 11 having clips 11a thereon. Also, the assembly process after the substrate 10 is attached to the boat 11 must be done slowly in order to ensure that the substrate 10 does not deviate from the boat 11, which limits overall productivity.
Thirdly, for the conventional BGA semiconductor package to be applied to high power devices such as a central processing unit (CPU), a heat sink which gives off heat must be attached to the back surface of the package body, which requires the overall package thickness to be greater than 3 mm, and thus limits the desired minimization in package size.
Fourthly, a low cost transfer molding process cannot be used for manufacturing the conventional package having a cavity down type structure which allows increased heat emission, and only an expensive liquid encapsulant can be used together with a dispenser for manufacturing the conventional package.